This invention relates to the technical field of a digital image recording apparatus and a light-sensitive material distributing device which is to be used in an image recording apparatus that exposes light-sensitive materials to record a latent image.
Heretofore, the image recorded on photographic films such as negatives and reversals (which are hereunder referred to simply as "films") has been commonly printed on light-sensitive materials such as photographic paper by means of direct (analog) exposure, in which projected light from the film is allowed to be incident on the light-sensitive material to achieve its areal exposure.
A new technology has recently been introduced and this is a printer that relies upon digital exposure. Briefly, the image recorded on a film is read photoelectrically, converted to a digital signal and subjected to various image processing operations to produce image data for recording purposes; recording light that has been modulated in accordance with the image data is used to scan and expose a light-sensitive material to record a latent image, which is subsequently developed and output as a print (photograph). The printer operating on this principle has been commercialized as a digital photoprinter.
In the digital photoprinter, the image on a film is read photoelectrically and gradation correction and other operations are performed by subsequent image (signal) processing to determine exposing conditions. Hence, the digital photoprinter has many capabilities in image processing such as editing of printed images by, for example, assembling a plurality of images or splitting a single image into plural images, as well as color/density adjustment and edge enhancement; as a result, prints can be output after various image processing operations have been performed in accordance with specific uses. In addition, the data on a printed image can be supplied into a computer or the like and stored in recording media such as a floppy disk.
A further advantage of the digital photoprinter is that compared to the prints produced by the conventional method of direct exposure, those which are output by the digital photoprinter have better image quality in such aspects as resolution and color/density reproduction.
Having these features, the digital photoprinter is basically composed of an input machine having a scanner (image reader) and an image processor and an output machine having both an exposing device and a developing device.
In the scanner, reading light issuing from a light source is allowed to be incident on a film, from which projected light carrying the image recorded on the film is produced and focused by an imaging lens to form a sharp image on an image sensor such as a CCD sensor, the image being then captured by photoelectric conversion and sent to the image processor as data for the image on the film (i.e., the image data signal). In the image processor, the image data sent from the scanner are subjected to specified image processing operations and the resulting output image data for image recording (i.e., exposing conditions) are sent to the exposing device.
In the exposing device, if it is of a type that relies upon exposure by scanning with an optical beam, the latter is modulated in accordance with the image data sent from the image processor and deflected in a main scanning direction as the light-sensitive material (e.g. photographic paper) is transported in an auxiliary direction perpendicular to the main scanning direction, whereby a latent image is formed as the result of scan exposure (printing) of the light-sensitive material with the optical beam and a back print is also recorded. In the developing device (processor), the exposed light-sensitive material is subjected to development and other specified processing operations so as to output a print which reproduces the image that has been recorded on the film.
In the exposing device, whether it is in the digital photoprinter or an ordinary photoprinter that relies upon "direct" exposure, a virgin light-sensitive material is in the form of a magazine, i.e., a roll contained in a lightproof case. The light-sensitive material is withdrawn out of the magazine in the exposing device and further transported for exposure and other necessary steps.
In the ordinary photoprinter, the light-sensitive material being transported is not cut but remains a web as it is subjected to exposure, back print recording, development, rinse, drying and other necessary steps and only after these steps are complete, the light-sensitive material is cut to individual prints of a specified length.
This process requires that frame information (frame punches) for delineating individual frames (or prints) be formed before or after the exposure of the light-sensitive material. However, the portion of the light-sensitive material where the frame information is formed is simply a waste of space. In addition, frame information have to be formed by special means having a punch, a sensor or the like.
In the exposing device of a digital exposure type, the light-sensitive material in the process of exposure must be transported for scanning in high precision and without stops in order to record images of high quality that are free from unevenness and other defects. On the other hand, the transport of the light-sensitive material has to be stopped at the time of forming frame information and, in addition, the recording of back prints will fluctuate the load in the transport of the light-sensitive material for scanning.
In order to avoid these difficulties, the exposing device in the digital photoprinter is adapted to make a slack (loop) out of the light-sensitive material which is located not only between the exposing position and the frame information forming zone but also between the exposing position and the back print recording zone. If this approach is taken, the volume of the light-sensitive material in loop (the number of frames) must be controlled, the timing of exposure must be properly adjusted and there are many other factors including the complexity of the transport zone and in the control of the light-sensitive material; as a result, the equipment cost and the running cost increase inevitably.
Under the circumstances, an exposing device is desired that can be incorporated in a digital photoprinter and which is capable of exposing a light-sensitive material after it is cut to sheets corresponding to individual prints to be finally produced.
However, the digital exposing device which is capable of exposing a light-sensitive material after it is cut to sheets has not been actually realized yet.
With photoprinters, development and subsequent steps generally take more time than exposure. If exposure (image recording) is performed continuously in parallel with development and subsequent steps, the former outpaces the latter and the exposed but yet to be developed light-sensitive material gradually builds up. In other words, the development and subsequent steps are rate limiting and the exposing operation has to be stopped.
In photoprinters of a type that cuts the light-sensitive material into sheets in the last step, a reservoir is provided between the exposing section and the developing machine to store the exposed light-sensitive material temporarily. As a result, the development and subsequent steps are not rate limiting and continuous exposure can be accomplished to realize efficient processing.
In photoprinters of a type that performs exposure after the light-sensitive material is cut into sheets, the operating efficiency can be improved by accommodating the sheets of exposed light-sensitive material in a stocker or the like. However, this approach involves difficulty in the management of the order of exposing the cut sheets (by making reference to the frame number and by sorting), as well as in achieving smooth ejection of the sheets from the stocker or the like.
To overcome this difficulty, the cut sheets of the exposed light-sensitive material, before they are fed into the developing machine, are distributed sidewise, or in a direction perpendicular to the direction of their transport, to form a plurality of rows that overlap in the direction of transport. In this way, the throughput of the developing machine can be improved over the case where individual sheets of the light-sensitive material are processed in a single row (almost doubled in two rows and tripled in three rows) and the difference in speed between exposure and development processing is practically cancelled.
However, if a device that performs such distribution of the sheets of light-sensitive material is provided in a photoprinter, the pathlength over which the light-sensitive material is transported is increased and the size of the photoprinter and its cost will increase unavoidably.
Distribution of the cut sheets of light-sensitive material should not affect exposure and any other steps in the processing of the light-sensitive material. Take, for example, a photoprinter that has a capability for processing 1800 prints of the most common size per hour. Since one print is processed (exposed) every two seconds, the distributing device must accordingly complete the necessary operation consisting of the acceptance of incoming sheets of the exposed light-sensitive material, their distribution and making preparations for the acceptance of the next coming sheet.
In order to meet this requirement, the conventional distributing device is adapted to consist of three blocks, a high-speed transport block, a distributing block and a speed regulating block; in the high-speed transport block, the sheets of light-sensitive material emerging from the exposing section are transported into the distributing block at high speed so that the distance to the next coming sheet is long enough to secure the time necessary for performing the intended distribution and in the distributing block, the sheets are distributed sidewise by a suitable method such as moving the sheets together with the transport means and thereafter transported into the speed regulating block, where the transport speed of the sheets is adjusted to one that is compatible with development before they are fed into the developing machine.
As a result, compared to the case where no such distributing device is employed, the pathlength of the light-sensitive material is increased considerably and the size and cost of the photoprinter will increase accordingly.